Theoretical And Experimental Study On Flexible MEMS Terahertz Metamaterial Modulators And Absorbers

Terahertz metamaterials have made tremendous progress in theoretical analysis and experimental research.Recently,some terahertz metamaterial devices are widely studied,such as terahertz metamaterial modulators,absorbers,sensors,etc.However,most of these devices are fabricated on rigid substrate and can’t be applied in curved situation.Thus,based on the resonance principle and structural design of terahertz metamaterials,this paper explores simulation,design,fabrication and testing of terahertz modulators and absorbers with flexible Parylene-C substrate.It mainly includes the following two parts:1)Two flexible terahertz metamaterial modulators were designed,which showed innovation and competitiveness in terms of flexibility,polarization independence,dual band,modulation method and fabrication technology.The first structure consisted of identical complementary Omega rings,which produced compression regulation in different directions along the X and Y axes,that was it could produce 21% single band amplitude modulation along the X-axis compression and could achieve dual band amplitude modulation along the Y-axis direction.In order to optimize the polarization independence of the first structure,we rotated its basic unit by 90° in sequence to form the second structure.The second structure produced dual-band reverse regulation during compression,that was,at low frequency,the amplitude increased as the compression displacement increased but it decreased when the compression displacement increased at high frequency.The good polarization independence of the second structure was demonstrated by compressed along X-axis and Y-axis.We used mechanical compression method,which was simple in structure design and was easy to fabrication.2)Flexible terahertz metamaterial absorbers were designed.We still used the Omega ring as the basic structure.At first,we explored the effect of the critical dimensions of the absorber on the absorption performance and determined the optimal size of structure.We designed two absorbers,the first of which was based on the identical Omega ring and produced multiple absorption peaks during 0–1.4 THz.The second absorber combined four identical Omega rings into a centrally symmetric structure,and because of the symmetrical structure,the absorption amplitude of the absorber did not vary with polarization angle and incidence angle.In addition,we have proposed a four-layer structure on the basis of the traditional sandwich construction,so that the device could be smoothly peeled off from the silicon substrate after fabrication,which helped to the wide application in curved surface.